Dry cell



Jan. l, 1952 A. P. DRUMMOND 2,580,654

DRY CELL Filed May '7, 1946 v INVENTOR ARTHUR P.oRuMMoNo BY f Il I l, [3-fU Y Patented Jan. l, 1952 OFFICE* p DRY CELL Arthur P. Drummond,Cleveland, Ohio, assimor, by mesne assignments, to Union Carbide andCarbon Corporation, a corporation of New York Application May '1, 194s,serial No. esmas' zouims. (criss-133) This invention relates to drycells, more particularly those of a size and shape intended forflashlights. An object of the invention is to provide a dry cell inwhich looseness of a jacket has been minimized or prevented. A furtherobject is to provide a contact fit to prevent egress of electrolytevmaterial at the ends of the cell without the necessity of having to useany adhesive or seal against electrolyte material coming out.

It has heretofore been suggested to use a sti. non-bulging, insulatingjacket of an appropriate resinous insulating material such as thatdescribed and claimed in the cor-pending application of Roland L.Glover, Serial No. 636,835, filed December 22, 1945, for Dry Cell, nowPatentA No. 2,552,091, dated May 8, 1951, on which this invention is animprovement. At first it was found too high a percentage of suchjacketed dry cells possessed looseness permitting slight longitudinalmovement and relative rotation between the cell and the jacket. `A studyof the difllculty has shown that the cause was the crimped rib betweenthe metal top and zinc being at such an angle that after spinning over,there was a tendency for the spun-over bead of the jacket to open a.little by yie'ding. Although the jacket was of stii non-bulging materialthe spun end appeared to possess some slight resilience. To avoid thisdifllculty the crimped rib has been disposed more nearly perpendicularto the cell axis so that the bead on the jacket may be spun over to aperipheral length more than is needed to hold it in place. The resulthas been that the previous looseness has not only been eliminated but atight enough fit'is obtained between .the jacket and the zinc to guardagainst egress of any electrolyte material which may exude `through thezinc without havingl to .use adhesive. 'Ihus the beaded jacket issupportedby the engagement of its ends with the ends of the cell.

The spun-over jacket ends are retained in their substantially closedposition without danger of opening by yielding to cause the jacket toappear loose.

-Referring to the drawings:

Fig. 1 is a partial longitudinal cross section through one embodiment ofthis invention;

Fig. 2 is a similar view of a modified construction;

Fig. 3 illustrates a step in the process of forming the dry cell of thisinvention;

'-`Fig. 4 is a partial longitudinal sectionof another embodiment; and

Fig. 5 illustrates a still further embodiment.

As described in the aforementioned Glover Patent No. 2,552,091, a carbonelectrode I0 is provided with a longitudinal and axial hole II overwhich a vented metal cap 24 is fitted. A conventional depolarizing mixI3 and immobilized electrolyte, material I4 are placed between thecarbon and zinc velectrode I5 leaving a gas chamber in the upper end ofthe cell. Surroundi118 the zinc is a stiff jacket I6 of celluloseacctate butyrate as described in the aforementioned application. A starwasher I 1 is located between the zinc bottomA I8 and the depolarizingmix. A blanket 3l is also used around the lower part of the depolarizingmix. A metal end or top I9 is crimped over the upper edge portion of thezinc electrode and separated from the metal cap 24 by an insulatingwasher 23. A gas-permeable washer or disc 22 divides the gas chamber atzo the top .of the cell in the usual manner.

'I'he early` efforts at applying the jacket I6 by spinning over its ends2li to form beads as illustrated were not wholly successful because theloop, or bead, or spun-over portion con- 25 tinued to open slightly byyielding at the top end only.` 'I'he loop at the bottom did not tend toopen or yield as did that at the top but held closed. The cells to whichthis jacket was first applied had the crimped joint between the zinc andmetal cover extending forwardly and outwardly at an acute angle ofapproximately 45 as had been customary in the art. Upon study it wasfound the loop or bead did not close, being prevented from doing so bythe upward inclination of the crimped joint. The result was a tendencyfor the spun-over loop to yield or tend to open to some extent with someof the cells. Such resulted in a noticeable looseness between the edgeof the cell and the jacket I5. In order to overcome this diiculty thecrimped joint between the zinc and metal cover has been arrangedhorizontally as illustrated with the result that it is possible for thespun-over end 20 of the stiff jacket to form a loop tangent to theincident top surface of the cover I9, the loop extending beyond thepoint of tangency and being spun over an amount more than enough to holdthe loop or bead locked in closed position with less tendency to yield.The improved construction is shown in Fig. l in which the upper bead orspun-over end of the jacket forms a loop which is nearly closed, thatis, in which the spun-over end is moved slightly past the point oftangency of the loop with the surface I9 for the purpose mentioned.

The embodiment 'shown in Fig. 2 is similar in many respects to thatillustrated in Fig. 1, the corresponding parts being designated by thesame referencenumerals as was done in Fig. l with the exception that theletter a is added. One important difference is that the ends 2l of thejacket loops 20a are tucked ln between the zinc and jacket asillustrated. Such a construction prevents the loop from theaforementioned yielding or opening and serves the novel purpose ofhaving the ends 2i of the jacket material function as spacers toseparate the jacket from the zinc wall, forming a larger volume exudantchamber 25a than was formed in Fig. 1 construction. Sealing material 26and 21 prevents loss of moisture from the exudant chamber as well asguarding against accidental. egress of electrolyte material. Althoughillustrated, this sealing material 28 and 21 is not believedto be alwaysnecessary but may be used with any of the illustrated embodiments of theinvention.

In Fig. 3 two labutments 31 and 38 are arranged to move relativelytoward one another no more than a predetermined distance equal to thelength desired for the finished cell before the jacket has been applied.In closing the abutment members 31 and 38 a spinning tool 39 deforms theupper edge of the cover as illustrated. The metal cover i9 may be spunor crimped over the zinc. The result is the formation of an exudantchamber 25 outside the zinc and within the jacket I6 for the purposementioned in the aforementioned Glover patent. If desired, perforationsshown in Fig. 3 may be made in the zinc either above or below thegas-permeable washer 22 in order that any gas pressure may be equalizedon each side of the zinc and not tend to deform the groove in the zinc.'Ihe jacket i6 may be placed contiguous to the zinc as illustrated or,if desired, a thin absorbent paper may be placed between the zinc andjacket for purposes referred to in said aforementioned application. Inthe embodiment illustrated in Fig. 1, there is no sealing materialaround the inner portion of the spun-over jacket loops. since such isnot ordinarily necessary although,

l of course, it may be used where great precautions against leakage ofelectrolyte are desired.

In .the embodiment illustrated in Fig. 4, the same reference numeralsdesignate similar parts except that the letter b has been`added. Onediiference in Fig. 4 is the presence of a second gas-permeable ring typewasher 28, the outer peripheral edge of which is received within andforms a part of the crimp 29 between the zinc and metal cover. Such aconstruction makes unnecessary the provision of vent holes in the upperend portion of the zinc above the washer 22h since the gas-permeablewasher 28 enables any gas pressures within the zinc to be vented intothe exudant chamber 25h. A second gaspermeable strip 30 is preferablylocated between the lower edge portion of the zinc and the insulatingjacket Iiib for the purpose of venting any gas pressure within theexudant chamber through the material 30. The contact between the metalcover and spun over bead 20h of the stiff insulating jacket material Ilbis thought to be tight enough to prevent egress of electrolyte materialbetween the metal top and such bead. The gas-permeable washer 30 isplaced in the position illustrated to insure venting the exudant chamberand also serves to space the lower portion of the insulating jacket |61)from the lower edge of the zinc. The jacket in each of Figs.

4 i, 2 and 4 is preferably of the same stiff cellulose acetate butyratematerial described in the aforementioned pending application. y.

In Fig. 5 a slightly diilerent construction is illustrated. The metalcover 33 is integral with the jacket 32, the jacket being merely acontinuation of the metal cover. As shown in P18. 5 the lower endportion of the metal jacket is bent at 34 contiguous to the metal bottom3l. In this embodiment the metal jacket 32 may be contiguous to the zinciSc or the metal bottom 35 may be extended to have its outer edgeportion bent up forming a spacer between the zinc and metal sleeve.Where the metal sleeve 32 is then spaced from the zinc an exudantchamber 25e is formed and the upper end portion of the sleeve is spacedfrom the zinc, preferably by means of a gas-permeable washer 38. Thebottom 35 may be contiguous to the bottom of the zinc in order toprovide a better mechanical reinforcement for the zinc bottom againstbulging under gas pressure with the cell or the bottom 35 may bearranged as illustrated. The outer surface of the jacket 32 ispreferably provided with an appropriate electric insulating resinou-'splastic coating for purposes of insulation and decoration. 'I'he metal32 is preferably of steel although it might be of aluminum with ananodized finish on both the inside and outside since such a finish ishard and a good electrical insulator. A gasket 40 between the zinc andmetal jacket enhances the leakproof character of the cell. Of coursethis gasket Il might be gas-permeable and extend between lower bent end3| of the jacket and the reinforcing bottom of the cell. Or the steeljacket might be coated on either or both the inside and outside surfacewith a thin layer of thermoplastic insulating material should it bedesired to insulate the jacket from the zinc. The metal jacket 32 may becontiguous to the zinc where no exudant chamber 25C is needed. Byexudant chamber is meant a space into which electrolyte material mayexude through the container electrode without causing leakage or bulgingunder ordinary usage of the cell.

By the term closed exudant chamber" is meant the provision of a spaceradially outside the outer electrode into which electrolyte material mayexude without leaking outside the cell or jacket under moderate internalpressure. The outer and end walls of such a space are ofelectrolyte-proof material, so that the jacket walls are not softenedand distorted by the exudant electrolyte material in drying.

I claim:

1. In a dry cell having an outer cylindrical electrode, electrolyte anddepolarizing material within said outer electrode, a jacket of stiffmaterial having an electrolyte-proof inner surface outside saidcylindrical electrode, a closed exudant chamber between said cylindricalelectrode and jacket and a metal cover crimped over the top edge of saidcylindrical electrode, the combination therewith of the improvement forincreasing the volume of said exudant chamber without increasing theover-al1 dimensions of said cell, said improvement comprising anenlargement in said exudant chamber adjacent the top of the cell above agas permeable insulating disc which is spaced above the electrolyte anddepolarizing materials, said enlargement being formed by the cylindricalelectrode being bowed radially inward with the upper edge portion o! 1|said cylindrical electrode extending .generally horizontally radiallyoutward from said bowed portion, said cover being crimped over saidoutwardly extending electrode edge, whereby any excess length in saidcylindrical electrode may be taken up in said inwardly bowed portion andthe enlargement in said exudant chamber made without increasing theoutside diameter of the cell or reducing the space in which electrolyteand depolarizing materials may be maintained.

2. In a dry cell having an outer cylindrical electrode, electrolyte anddepolarizing material Within said outer electrode, a jacket of stiimaterial having an electrolyte-proof inner surface outside saidcylindrical electrode, a closed exudant chamber between said cylindricalelectrode and jacket and a metal cover crimped over the top edge of saidcylindrical electrode, the combination therewith of the improvement forincreasing the volume of said exudant chamber and for reducing thedanger of longitudinal looseness between the jacket and cell, saidimprovement comprising an enlargement in said exudant chamber adjacentthe top of the cell above the electrolyte and depolarizing materials,said enlargement being formed by the cylindrical electrode being bowedradially inward with the upper edge portion of said cylindricalelectrode extending generally horizontally radially outward, said coverbeing crimped over said outwardly extending electrode edge, whereby anyexcess length in said cylindrical electrode may be taken up in saidinwardlybowed portion and the enlargement in said exudant chamber madewithout increasing the outside diameter of the cell or reducing thediameter of the space in which the electrolyte and depolarizingmaterials are maintained, the stii jacket being supported at each end bya bead spun over far enough to stay closed and not yield under anytendency for relative longitudinal movement between said jacket andcell.

ARTHUR P. DRUMMOND.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 174,821 Johnson Mar. 14, 1876439,151 Hellesen Oct. 28, 1890 1,199,390 Landau Sept. 26, 1916 1,500,477Warncke July 8. 1924 1,590,749 Hulbert June 29, 1926 1,679,629 RollmanAug. 7, 1928 1,711,182 Shrum Apr. 30, 1929 2,006,691 Giesler July 2,1935 2,011,519 Holst et al Aug. 13. 1935 2,179,816 Drummond Nov. 14,1939 2,262,836 Deibel Nov. 18, 1941 2,332,456 McEachron et al. Oct. 19,1943 2,337,452 Compo Dec. 21, 1943 2,392,795 Anthony et al. Jan. 8. 19462,396,693 Glover Mar. 19, 1946 2,399,089 Anthony Apr. 23, 1946 2,410,826Lang et al. Nov. 12, 1946 2,427,561 Keller Sept. 16, 1947 2,440,401Hirtle Apr. 27, 1948 2,482,514 Ruben Sept. 20, 1949 FOREIGN PATENTSNumber Country Date 330,690 Great Britain June 19. 1930 360,657 GermanyOct. 5, 1922 411,434 Great Britain June 1, 1934 684,550 Germany Nov. 30,1939 OTHER REFERENCES Mills: Top and Bottom Attachments," ProductEngineering, August 1945. pages 544 and 545.

